Process for preparing alpha, omega-haloperfluoroalkanes

Abstract

A process for preparing alpha , omega -dihaloperfluoroalkanes consisting in dihalogenating alpha , omega -diiodoperfluoroalkanes, or alpha , omega -chloroiodoperfluoroalkanes or alpha , omega -bromoiodoperfluoroalkanes with Cl2 or Br2.

What is claimed is: 
     
       1. A process for preparing tetrafluoroethylene telomers of the formula X(C 2  F 4 ) n  Y, wherein n is an integer from 2 to 6, and X and Y, the same or different, are Cl or Br, which comprises: (a) telomerizing tetrafluoroethylene with a telogen of the formula Z(C 2  F 4 )I, wherein Z is I, Br, or Cl, to form a telomer of the formula Z(C 2  F 4 ) n  I, and   (b) reacting Z(C 2  F 4 ) n  I with chlorine or bromine at a temperature between 0° and 180° C. in the absence of solvent or diluent.   
     
     
       2. The process according to claim 1, wherein n is an integer from 2 to 4. 
     
     
       3. The process according to claim 1, wherein telomerization is effected at a temperature between 150° to 250° C. 
     
     
       4. The process according to claim 1, wherein telomerization is effected at a temperature between 45° and 250° in the presence of an organic peroxide. 
     
     
       5. The process according to claim 1, wherein Z(C 2  F 4 ) n  I is reacted with from 0.5 to 10 moles of chlorine or bromine per atom of iodine. 
     
     
       6. The process according to claim 5, wherein Z(C 2  F 4 ) n  I is reacted with from 1 to 5 moles of chlorine or bromine per atom of iodine. 
     
     
       7. The process according to claim 1, wherein the reaction of Z(C 2  F 4 ) n  I with chlorine or bromine is effected at a temperature between 50° and 180° C. 
     
     
       8. The process according to claim 1, wherein the reaction of Z(C 2  F 4 ) n  I with chlorine or bromine is effected at a temperature between 0° and 50° in the presence of UV radiation. 
     
     
       9. The process according to claim 1, wherein the reaction of Z(C 2  F 4 ) n  I with chlorine or bromine is effected under the autogenous pressure of the chlorine or the bromine. 
     
     
       10. The process according to claim 1, wherein the reaction of Z(C 2  F 4 ) n  I with chlorine or bromine is effected at ambient pressure.